Uplink radio resource allocation method, radio base station, and radio network controller

ABSTRACT

An uplink radio resource allocation method allocates, at a radio base station, an uplink radio resource used for uplink user data transmission to a mobile station. The method includes: allocating, at the radio base station, the uplink radio resource, so that total received power in an particular cell of the radio base station is equal to a first target value assigned by a radio network controller; and allocating, at the radio station, the uplink radio resource, so that a ratio of first received power from a serving mobile station to second received power from a non-serving mobile station is equal to a second target value assigned by the radio network controller, a serving cell of the serving mobile station being the particular cell, a non-serving cell of the non-serving mobile station being the particular cell.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. P2005-033716, filed on Feb. 9,2005; the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an uplink radio resource allocationmethod for allocating, at a radio base station, an uplink radio resourceused for uplink user data transmission to a mobile station, a radio basestation and a radio network controller.

2. Description of the Related Art

In a general mobile communication system, between one of radio basestations Node B (refer to FIG. 1A) arranged in a cellular pattern and amobile station UE, user data is transmitted through a radiocommunication link.

Here, as shown in FIG. 1B, a radio communication link used fortransmitting user data from the radio base station Node B to the mobilestation UE is referred to as “a downlink” and a radio communication linkused for transmitting user data from the mobile station UE to the radiobase station Node B is referred to as “an uplink.”

The radio base station Node B can simultaneously perform communicationswith a plurality of mobile stations UE visiting one cell.

Note that, as shown in FIG. 1C, for the purpose of increasing a radiocapacity, a cell controlled by the radio base station Node B is dividedinto a plurality of sectors by using a plurality of directional antennas(sector antennas).

Additionally, as shown in FIG. 1D, a radio resource used between themobile station UE and the radio base station Node B is managed by aradio network controller RNC connected to the radio base station Node Bthrough a wired transmission channel.

Note that the radio network controller RNC is normally configured tocentrally control a plurality of radio base stations Node B.

By using FIG. 2, a description will be given of an uplink radio resourcein a mobile communication system where CDMA (Code Division MultipleAccess) is used for a radio access method.

In uplinks in the above communication system, each of a plurality ofmobile stations UE, after applying encoding and modulation processes touplink user data, transmits the user data by spreading the data into thesame wide frequency range by using a spread code specific to each of themobile stations UE.

On the other hand, after performing despreading on the uplink user databy using a spread code specific to each of the mobile stations UE uponreceipt of radio signals relating to the data, the radio base stationNode B decodes the data from the respective mobile stations UE byapplying filtering, demodulation and decoding processes to the data.

In this case, with a signal from an intended mobile station, signalsfrom the other mobile stations transmitting uplink user data becomeinterference signals.

Therefore, if there are too many of other mobile stations transmittingthe uplink data, or if an uplink transmission rate of the other mobilestations is too high (that is, uplink transmission power thereof is toohigh), the radio base station Node B is disabled to correctly decode theuplink user data of the intended mobile station.

Therefore, in the uplinks in the above mobile communication system,total received power (total interference power) in the radio basestation Node B becomes “an uplink radio resource” shared by theplurality of mobile stations UE.

Here, in the case where the cell controlled by the radio base stationNode B is divided into the plurality of sectors, since directivity isprovided to each of the sectors, uplink radio resources (uplinkinterference power) shared by mobile stations UE are independent fromone another between the respective sectors.

Therefore, the amount of the uplink radio resources (the uplinkinterference power) in the cell controlled by the radio base stationNode B increases with increasing the number of the sectors (in otherwords, a radio capacity increases with increasing the number of thesectors).

By using FIGS. 3A to 3E, a description will be given of transmissionpower control and “other-cell (other-sector) interference” in the mobilecommunication system to which CDMA (Code Division Multiple Access) isapplied.

As described above, in the above mobile communication system, totalinterference power in the radio base station Node B becomes a radioresource shared by a plurality of the mobile stations UE.

Therefore, the radio base station Node B controls the transmission powerof the respective mobile stations UE, so that the received power isequal to minimum received power required to satisfy uplink communicationquality between the radio base station Node B and each of the mobilestations UE.

In this case, the minimum received power required to satisfy uplinkcommunication quality (hereinafter, referred to as required receivedpower of radio base station) mainly depends on an uplink transmissionrate of the mobile stations UE (i.e., a transmission rate of uplink userdata) although it also changes depending on transmission environment andon moving speed of the mobile stations UE.

Here, the required received power of radio base station changes inproportion to the uplink transmission rate of the mobile station UE, andas shown in FIG. 3A, twice as much as the required received power ofradio base station is needed if the uplink transmission rate becomesdouble.

To the contrary, if the uplink transmission rate is unchanged, therequired received power of radio base station is unchanged regardless ofa location of the mobile station UE visiting a particular cell (sector).

On the other hand, power of a radio signal attenuates with increasingdistance through which data is transmitted. Therefore, as shown in FIGS.3B and 3C, the radio base station Node B is configured to control, evenwhen an uplink transmission rate of the mobile station UE is constant,transmission power of each of the mobile stations UE in the followingmanner.

The radio base station Node B reduces the “transmission power in mobilestation” if the mobile station UE is near the base station Node B, andrises the “transmission power in mobile station” if the mobile stationUE is far from the base station Node B.

However, since a transmission antenna of the mobile station UE does nothave directivity, uplink transmission from the mobile station UE reachesnot only a sector of the radio base station Node B to which the mobilestation UE is connected through an uplink, but also another sector ofthe same radio base station Node B or a cell of a neighboring radio basestation Node B, becomes interference in those cells (sectors).

The thus described interference caused in a neighboring cell (sector) bythe transmission power from the mobile station UE will be referred to as“other-cell (other-sector) interference” (refer to FIGS. 3D and 3E).

By using FIG. 4, a description will be given of a conventional uplinkradio resource control method in the mobile radio communication systemto which CDMA (Code Division Multiple Access) is applied.

Conventionally, a radio network controller RNC has been performing acall admission control process and an uplink transmission rateallocation process with respect to each mobile station UE.

By referring to both transmission power, transmitter performance, atransmission rate required by an application thereof and the like of amobile station UE requesting a connection via a dedicated channel (DCH),the radio network controller RNC accepts a connection request from themobile station UE and determines an uplink transmission rate allocatedto the mobile station UE in a range such that total interference powerin a cell (sector) to which an uplink is intended to be set up and inneighboring cells (sectors) thereof respectively does not exceed maximumallowable interference power.

Subsequently, through a layer-3 (RRC: Radio Resource Control) message,the radio network controller RNC notifies the radio base station Node Band the mobile station UE of acceptance of the connection request fromthe mobile station UE, and of the uplink transmission rate.

Specifically, the radio network controller RNC allocates an uplinktransmission rate to a mobile station UE requesting a connection via aDCH in the following manners.

(1) If the radio network controller RNC judges that total interferencepower in a cell (sector) to which an uplink is intended to be set up andin neighboring cells (sectors) thereof does not exceed the maximumallowable interference power respectively, it accepts a connectionrequest from the mobile station UE, and allocates an intended uplinktransmission rate.(2) If the radio network controller RNC judges that total interferencepower in at least any one of a cell (sector) to which an uplink isintended to be set up and in neighboring cells (sectors) thereof exceedsthe maximum allowable interference power respectively, it accepts aconnection request from the mobile station UE. However, it allocates anuplink transmission rate which is lower than an intended uplinktransmission rate and which is in a range such that total interferencepower in the cell (sector) to which the uplink is intended to be set upand in the neighboring cells (sectors) thereof do not exceed the maximumallowable interference power respectively.(3) If the radio network controller RNC judges that total interferencepower in at least any one of a cell (sector) to which an uplink isintended to be set up and in neighboring cells (sectors) exceeds themaximum allowable interference power, it accepts a connection requestfrom the mobile station UE. However, by lowering an uplink transmissionrate allocated to another mobile station in the cell (sector) to whichthe uplink is intended to be set up or in neighboring cells (sectors)thereof, it allocates an uplink transmission rate in a range such thattotal interference power in the cell (sector) to which an uplink isintended to be set up and in the neighboring cells (sectors) thereofdoes not exceed the maximum allowable interference power respectively.(4) If the radio network controller RNC judges that total interferencepower in at least any one of a cell (sector) to which an uplink isintended to be set up and neighboring cells (sectors) thereof exceedsthe maximum allowable interference power respectively, it performs bothcontrols of (2) and (3).(5) If the radio network controller RNC judges that total interferencepower in at least any one of a cell (sector) to which an uplink isintended to be set up and in neighboring cells (sectors) thereof exceedsthe maximum allowable interference power respectively, it does notaccept a connection request from the mobile station UE.

Thus, since the radio network controller RNC normally centrally controlsa large number of radio base stations Node B, it can efficientlyallocate, by referring to uplink transmission states of mobile stationsUE communicating with the respective radio base stations Node B, andalso by referring to other-cell (other-sector) interference in therespective radio base stations Node B, uplink radio resources amongmobile stations UE requesting connections to the radio base stationsNode B.

By using FIGS. 5A to 5C, a description will be given of problems in thecase where the radio network controller RNC performs radio resourcecontrol on an uplink in a conventional mobile radio communication systemto which CDMA (Code Division Multiple Access) is applied.

Generally, in data communications, traffic often arises in a burstingmanner as compared with voice communications and TV communications.Therefore, naturally, it is desired that a channel transmission rateused for data communications be changed to a high speed.

However, as shown in FIGS. 5A to 5C, the radio network controller RNCnormally centrally controls a large number of radio base stations NodeB, and therefore, in the conventional communication system, for reasonssuch as processing loads and processing delays, there has been a problemthat it is difficult for the radio network controller RNC to performalteration control on a transmission rate of a high-speed channel (in arange approximately of 1 to 100 ms).

Additionally, in the conventional communication system, even if theradio network controller RNC can perform the alteration control on thetransmission rate of a high-speed channel (in a range approximately of 1to 100 ms), there has been a problem that an equipment installation costand a network operating cost become considerably high.

Therefore, in the conventional communication system, it is a commonpractice that the radio network controller RNC performs alterationcontrol of a transmission rate of the channel in the order of severalhundred milliseconds to several seconds.

Accordingly, in the conventional communication system, in a case wheredata transmission in a bursting manner is performed as shown in FIG. 5A,the data transmission is performed by any one of ways respectively shownin FIGS. 5B and 5C.

In FIG. 5B, the data transmission is performed by allowing a low speed,a high delay and a low transmission efficiency, and in FIG. 5C, the datatransmission is performed by securing a radio resource for a high-speedcommunication and thus by allowing a radio bandwidth resource in avacant time and a hardware resource in a radio base station Node B to bewasted.

Consequently, in “3GPP” and “3GPP2” which are internationalstandardization organizations for a 3rd Generation Mobile CommunicationSystem, high-speed radio resource control methods in a layer-1 between aradio base station Node B and a mobile station UE, and in a MACsub-layer (a layer-2) have been studied for the purpose of makingefficient use of a radio resource.

Hereinafter, the study itself and functions studied therein arecollectively referred to as “enhanced uplink (EUL)”.

By using FIGS. 6A to 6B, a description will be given of a differencebetween “a radio resource control process according to a conventionalmethod” and “a radio resource control process according to an EULmethod” in an uplink in a mobile radio communication system to whichCDMA (Code Division Multiple Access) is applied.

In the EUL method, in contrast to the conventional method where theradio resource control process is performed by a radio networkcontroller RNC, the radio resource control process is configured to beperformed directly by radio base stations Node B.

In the EUL method, the maximum allowable interference power in cells(sectors) are notified to the respective radio base stations Node B bythe radio network controller RNC.

Then, the radio base station Node B instantly determines uplinktransmission rates of respective mobile stations UE in a range such thattotal interference power in the cell does not exceed the maximumallowable reference power notified by the radio network controller RNC,by referring to transmission power, transmitter performance of themobile stations UE, transmission rates needed by applications thereofand the like of the mobile stations UE connected to its own cell(sectors) through E-DCH.

Subsequently, the radio base station Node B notifies the determineduplink transmission rates to each of the mobile stations UE as a layer-1or MAC sub-layer massage.

In the above manner, the radio base station Node B accepts connectionrequests of the mobile stations UE, and determines the uplinktransmission rates allocated to the mobile stations UE (refer to FIGS.6A and 6B).

Consequently, the uplink transmission rates of the mobile stations UEcan be dynamically controlled into high speeds (in a range of 2 to 10ms, for example), whereby it becomes possible to make efficient use ofthe uplink radio resource.

By using FIG. 7, a description will be given of problems in the EULmethod where radio resource control is performed directly by a radiobase station Node B.

In the EUL method, because the radio resource control is performeddirectly by the radio base station Node B, there arises a problem thatan uplink radio resource cannot be allocated by, as is performed in theconventional method, referring to uplink transmission states andother-cell (other-sector) interference of mobile stations UEcommunicating with neighboring radio base stations Node B.

Consequently, if the radio base station Node B is aware only ofconstantly making efficient use of a radio resource in its own cell(sectors) and of satisfying desired transmission rates of mobilestations UE connected through E-DCH to its own cell (sectors), itresults in causing a great deal of other-cell (other-sector)interference in the neighboring radio base stations Node B.

In this case, a transmission rate of each of the mobile stations UEconnected to one of the neighboring radio base stations Node B isrestricted, and hence, required communication quality therebetweencannot be satisfied. It is considered that, at worst, a call from themobile station UE is disconnected.

As described above, in the EUL method, an uplink transmission rate of amobile station UE can be dynamically controlled into a high speed (in arange of 2 to 10 ms, for example) by having uplink radio resourcecontrol performed directly by the radio base station Node B.

However, by having the uplink radio resource control performed directlyby the radio base station Node B, there arises a problem that an uplinkradio resource cannot be allocated by, as is performed in theconventional method, referring to both uplink transmission states andother-cell (other-sector) interference of mobile stations UEcommunicating with the neighboring radio base stations Node B.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in consideration of theabove points, and objects of the present invention are to provide anuplink radio resource allocation method, a radio base station, and aradio network controller which, even in a mobile communication systemwhere radio resource control on uplinks is performed directly by theradio base station Node B, allow uplink radio resources shared amongradio base stations Node B (among cells) to be efficiently allocated andthus allow both communication quality degradation and calldisconnections in an uplink of each mobile station UE to be prevented.

A first aspect of the present invention is summarized as an uplink radioresource allocation method for allocating, at a radio base station, anuplink radio resource used for uplink user data transmission to a mobilestation, including: allocating, at the radio base station, the uplinkradio resource, so that total received power in an particular cell ofthe radio base station is equal to a first target value assigned by aradio network controller; and allocating, at the radio station, theuplink radio resource, so that a ratio of first received power from aserving mobile station to second received power from a non-servingmobile station is equal to a second target value assigned by the radionetwork controller, a serving cell of the serving mobile station beingthe particular cell, a non-serving cell of the non-serving mobilestation being the particular cell.

A second aspect of the present invention is summarized as a radio basestation which allocates an uplink radio resource used for uplink userdata transmission to a mobile station, including: a first radio resourceallocation section configured to allocate the uplink radio resource, sothat total received power in a particular cell of the radio base stationis equal to a first target value assigned by a radio network controller;and a second radio resource allocation section configured to allocatesthe uplink radio resource, so that a ratio of first received power froma serving mobile station to second received power from a non-servingmobile station is equal to a second target value assigned by the radionetwork controller, a serving cell of the serving mobile station beingthe particular cell, a non-serving cell of the non-serving mobilestation being the particular cell.

A third aspect of the present invention is summarized as a radio networkcontroller used in an uplink radio resource allocation method forallocating, at a radio base station, an uplink radio resource used foruplink user data transmission to a mobile station, including: a firsttarget value assignation section configured to assign a first targetvalue as a target value for total received power in a particular cell ofthe radio base station, the first target value used when the radio basestation allocates the uplink radio resource; and a second target valueassignation section configured to assign a second target value as atarget value for a ratio of first received power from a serving mobilestation to second received power from a non-serving mobile station, thesecond target value used when the radio base station allocates theuplink radio resource, a serving cell of the serving mobile stationbeing the particular cell, a non-serving cell of the non-serving mobilestation being the particular cell.

A fourth aspect of the present invention is summarized as an uplinkradio resource allocation method for allocating, at a radio basestation, an uplink radio resource used for uplink user data transmissionto a mobile station, including: comparing, at the radio base station,total received power in an particular cell of the radio base stationwith a first target value assigned by a radio network controller;comparing, at the radio base station, a ratio of first received powerfrom a serving mobile station to second received power from anon-serving mobile station with a second target value assigned by theradio network controller, when the total received power is not largerthan the first target value, a serving cell of the serving mobilestation being the particular cell, a non-serving cell of the non-servingmobile station being the particular cell; and maintaining, at the radiobase station, the uplink radio resource allocated to the non-servingmobile station unchanged, when the ratio is not smaller than the secondtarget value.

In the fourth aspect, the step of comparing the total received powerwith the first target value can include a step of checking whether ornot the total received power is larger than the first target value.

In the fourth aspect, the step of comparing the total received powerwith the first target value can further include a step of checkingwhether or not the total received power is equal to the first targetvalue.

In the fourth aspect, the step of comparing the ratio with the secondtarget value can be executed, when the total received power is equal tothe first target value.

A fifth aspect of the present invention is summarized as a radio basestation which allocates an uplink radio resource used for uplink userdata transmission to a mobile station, including; a first comparisonsection configured to compare total received power in an particular cellof the radio base station with a first target value assigned by a radionetwork controller; a second comparison section configured to compare aratio of first received power from a serving mobile station to secondreceived power from a non-serving mobile station with a second targetvalue assigned by the radio network controller, when the total receivedpower is not larger than the first target value, a serving cell of theserving mobile station being the particular cell, a non-serving cell ofthe non-serving mobile station being the particular cell; and a resourceallocation section configured to maintain the uplink radio resourceallocated to the non-serving mobile station unchanged, when the ratio isnot smaller than the second target value.

In the fifth aspect, the first comparison section can be configured tocheck whether or not the total received power is larger than the firsttarget value.

In the fifth aspect, the first comparison section can be configured tocheck whether or not the total received power is equal to the firsttarget value.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A to 1D are diagrams for explaining a conventional mobilecommunication system.

FIG. 2 is a diagram for explaining the conventional mobile communicationsystem.

FIGS. 3A to 3E are diagrams for explaining the conventional mobilecommunication system.

FIG. 4 is a diagram for explaining the conventional mobile communicationsystem.

FIGS. 5A to 5C are diagrams for explaining the conventional mobilecommunication system.

FIGS. 6A and 6B are diagrams for explaining the conventional mobilecommunication system.

FIG. 7 is a diagram for explaining the conventional mobile communicationsystem.

FIG. 8 is an entire configuration diagram of a mobile communicationsystem according to one embodiment of the present invention.

FIG. 9 is a channel configuration diagram of the mobile communicationsystem according to the embodiment of the present invention.

FIG. 10 is a diagram showing a breakdown of total received power in aradio base station in the mobile communication system according to theembodiment of the present invention.

FIG. 11 is a diagram for explaining operations of the mobilecommunication system according to the embodiment of the presentinvention.

FIG. 12 is a flowchart showing the operations of the mobilecommunication system according to the embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION A Configuration of a MobileCommunication System According to a First Embodiment of the PresentInvention

With reference to FIGS. 8 to 10, a description will be given of aconfiguration of a mobile communication system according to a firstembodiment of the present invention

In the mobile communication system according to this embodiment,transmission of user data is performed through a radio communicationlink between each of radio base stations Node B arranged in a cellularpattern and a mobile station UE.

Here, a cell controlled by each of the radio base stations Node B may bedivided into a plurality of sectors. Additionally, a plurality of basestations Node B are centrally controlled by a radio network controllerRNC.

Note that, in the present detailed description, unless particularlystated, a notion of a cell includes a notion of a sector.

In the mobile communication system according to this embodiment, the EULmethod is applied to transmission of uplink user data, and the radiobase stations Node B are configured to control transmission rates ofmobile stations UE.

Here, with reference to FIG. 8, a description will be given of mainphysical channels set up between each of the mobile stations UE#1 andUE#2 and the radio base stations Node B.

In an uplink, an E-DPDCH (E-DCH Dedicated Physical Data Channel) is setup, whereby the mobile station UE transmits uplink user data to theradio base station Node B by using the E-DPDCH.

In a downlink, an E-AGCH (E-DCH Absolute Grant Channel) and an E-RGCH(E-DCH Relative Grant Channel) are set up, whereby the radio basestation Node B transmits, to the mobile stations UE#1 and UE#2,information on an uplink radio resource (a transmission rate ortransmission power) allocated to the mobile stations UE#1 and UE#2 byusing the E-AGCH and E-RGCH.

Specifically, to the mobile station UE, the radio base station Node Bnotifies an absolute value of the uplink radio resource allocated to themobile station UE by using the E-AGCH, and notifies a relative value(up/down) of the uplink radio resource allocated to the mobile stationUE by using the E-RGCH.

Furthermore, soft handover is applied to the mobile communication systemaccording to this embodiment.

Here, a description will be given of the soft handover in uplink userdata transmission to which the EUL method is applied.

Normally, a mobile station UE is connected to a radio base station NodeB (cell) which is the best in radio communication link quality, and sucha radio base station Node B as above is referred to as “a serving cell”of the mobile station. UE.

Additionally, if there is a different cell which is not very poor inradio communication link quality as compared to the serving cell, themobile station UE is connected also to the different cell, which isreferred to as “a non-serving cell” of the mobile station UE.

This state is referred to as “soft handover”.

Here, normally, a mobile station UE located in the center of a cell isconfigured to connect to only one cell, and a mobile station UE locatedin an outskirt of a cell is configured to perform the soft handover.

In the soft handover state, all of cells to which the mobile station UEis connected attempt demodulation of uplink user data which the mobilestation UE transmits by using the E-DPDCH.

However, it is only the serving cell that can leadingly allocate anuplink radio resource to the mobile station UE by using the E-AGCH andE-RGCH.

The non-serving cell can only restrict, by using the E-RGCH without “up”(that is, only with “down”, which will be hereinafter referred to as anon-serving E-RGCH), the uplink radio resource used by the mobilestation UE.

With reference to FIGS. 9 and 10, a description will be given of radioresource control in the EUL method applied to the mobile communicationsystem according to the present invention.

As shown in FIG. 10, total received power (total interference power) ina radio base station Node B consists of received power (hereinafter,referred to as serving received power) from mobile stations for whichits own cell is working as a serving cell (hereinafter, referred to asserving mobile stations), and received power from mobile stations forwhich other cells are working as serving cells.

Furthermore, the received power from mobile stations for which othercells work as serving cells is broken down into: received power(hereinafter, referred to as non-serving received power) from mobilestations for which its own cell is working as a non-serving cell(hereinafter, referred to as non-serving mobile stations), and receivedpower (hereinafter, referred to as pure interference power) from mobilestations for which its own cell is not working as a non-serving cell(hereinafter, referred to as interference mobile stations).

Here, although the radio base station Node B can control the servingreceived power at its own judgment by using the E-AGCH and E-RGCH, andcan restrict the non-serving received power by using the non-servingE-RGCH, it cannot control at all the pure interference power (and noisepower).

Operations of the Mobile Communication System According to the FirstEmbodiment of the Present Invention

With reference to FIGS. 11 to 12, a description will be given ofoperations of the mobile communication system according to the firstembodiment of the present invention.

As shown in FIG. 11, for each of the radio base stations Node B, atarget value A (first target value) for the maximum total received powerin each of the cells, and a target value B (second target value) for aratio of serving received power (first received power) to non-servingreceived power (second received power) are assigned in advance by theradio network controller RNC.

The ratio of the serving received power to the non-serving receivedpower is a value calculated by dividing the serving received power bythe non-serving received power.

As shown in FIG. 12, in Step S101, each of the radio base stations NodeB measures total received power in each of the cells on a periodicbasis, that is, every 2 to 10 ms for example.

In Step S102, the radio base station Node B compares the measured totalreceived power with the target value A (first target value) for themaximum total received power assigned by the radio network controllerRNC.

If the measured total received power is higher than the target value A,the radio base station Node B, by using the E-AGCH or the E-RGCH,reduces uplink radio resources allocated to serving mobile stationsthereof in Step S103.

On the other hand, if the measured total received power is lower thanthe target value A, the radio base station Node B, by using the E-AGCHor E-RGCH, increases uplink radio resources allocated to the servingmobile stations in order to bring the total received power closer to thetarget value A in Step S105.

Additionally, in parallel with the above steps, each of the radio basestations Node B calculates a ratio of the serving received power to thenon-serving received power on a periodic basis, that is, every 2 to 10ms for example.

In Step S106, the radio base station Node B compares the calculatedratio of the serving received power to the non-serving received powerwith the target value B of the ratio of the serving received power tothe non-serving received power assigned by the radio network controllerRNC.

If the calculated ratio of the serving received power to the non-servingreceived power is lower than the target value B, the radio base stationNode B, by using the non-serving E-RGCH, restricts uplink radioresources used by the non-serving mobile stations in order to bring theratio closer to the target value B in Step S107.

However, if the calculated ratio of the serving received power to thenon-serving received power is higher than the target value B, the radiobase station Node B does not restrict uplink radio resources used by theserving mobile stations.

Effects and Advantages of the Mobile Communication System According tothe First Embodiment of the Present Invention

In the mobile communication system according to the first embodiment ofthe present invention, even if the mobile communication system whereinradio resource control on uplinks is performed directly by a radio basestation Node B, uplink radio resources shared among radio base stationsNode B can be efficiently allocated, and thus, both degradation ofcommunication quality and call disconnections in uplinks of the mobilestations UE can be prevented

According to the present invention, it is possible to provide an uplinkradio resource allocation method, a radio base station, and a radionetwork controller which, even in a mobile communication system whereradio resource control on uplinks is performed directly by the radiobase station Node B, allow uplink radio resources shared among radiobase stations Node B (among cells) to be efficiently allocated and thusallow both communication quality degradation and call disconnections inan uplink of each mobile station UE to be prevented.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and the representative embodimentsshown and described herein. Accordingly, various modifications may bemade without departing from the scope of the general inventive conceptas defined by the appended claims and their equivalents.

1.-9. (canceled)
 10. An uplink radio resource allocation method forallocating, at a radio base station, an uplink radio resource used foruplink user data transmission to a mobile station, comprising: step (A)notifying, from the radio base station to a serving mobile station whichconnects to an particular cell of the radio base station as a servingcell, an increase/a reduction of the uplink radio resource allocated tothe serving mobile station by using a first E-RGCH; and step (B)notifying, from the radio base station to a non-serving mobile stationwhich connects to the particular cell of the radio base station as anon-serving cell, a restriction of the uplink radio resource allocatedto the serving mobile station by using a second E-RGCH; wherein theradio base station maintains, in step (B), without using the secondE-RGCH, the uplink radio resource allocated to the non-serving mobilestation unchanged, when total received power in the particular cell ofthe radio base station is not larger than a first target value assignedby a radio network controller.
 11. An uplink radio resource allocationmethod for allocating, at a radio base station, an uplink radio resourceused for uplink user data transmission to a mobile station, comprising:step (A) notifying, from the radio base station to a serving mobilestation which connects to an particular cell of the radio base stationas a serving cell, an increase/a reduction of the uplink radio resourceallocated to the serving mobile station by using a first E-RGCH; andstep (B) notifying, from the radio base station to a non-serving mobilestation which connects to the particular cell of the radio base stationas a non-serving cell, a restriction of the uplink radio resourceallocated to the serving mobile station by using a second E-RGCH;wherein the radio base station maintains, in step (B), without using thesecond E-RGCH, the uplink radio resource allocated to the non-servingmobile station unchanged, when received power from the serving mobilestation and received power from the non-serving mobile station satisfy apredetermined condition.
 12. The uplink radio resource allocation methodaccording to claim 11, wherein the radio base station determines thatreceived power from the serving mobile station and received power fromthe non-serving mobile station satisfy the predetermined condition whena ratio of received power from a serving mobile station to receivedpower from a no-serving mobile station is not smaller than a secondtarget value.
 13. A radio base station which allocates an uplink radioresource used for uplink user data transmission to a mobile station,comprising: a first resource allocation section configured to notify, toa serving mobile station which connects to a particular cell of theradio base station as a serving cell, an increase/a reduction of theuplink radio resource allocated to the serving mobile station by using afirst E-RGCH; and a second resource allocation section configured tonotify, to a non-serving mobile station which connects to the particularcell of the radio base station as a non-serving cell, a restriction ofthe uplink radio resource allocated to the serving mobile station byusing a second E-RGCH; wherein the second resource allocation section isconfigured to maintain, without using the second E-RGCH, the uplinkradio resource allocated to the no-serving mobile station unchanged,when received power from the serving mobile station and received powerfrom the non-serving mobile station satisfy a predetermined condition.14. A radio base station which allocates an uplink radio resource usedfor uplink user data transmission to a mobile station, comprising: afirst resource allocation section configured to notify, to a servingmobile station which connects to a particular cell of the radio basestation as a serving cell, an increase/a reduction of the uplink radioresource allocated to the serving mobile station by using a firstE-RGCH; and a second resource allocation section configured to notify,to a non-serving mobile station which connects to the particular cell ofthe radio base station as a non-serving cell, a restriction of theuplink radio resource allocated to the serving mobile station by using ssecond ERGCH; wherein the second resource allocation section isconfigured to maintain, without using the second E-RGCH, the uplinkradio resource allocated to the non-serving mobile station unchanged,when received power from the serving mobile station and received powerfrom the no-serving mobile station satisfy a predetermined condition.15. The radio base station according to claim 14, wherein the secondresource allocation section is configured to determine that receivedpower from the serving mobile station and received power from thenon-serving mobile station satisfy the predetermined condition when aratio of received power from a serving mobile station to received powerfrom a non-serving mobile station is not smaller that a second targetvalue.
 16. A radio network controller used in an uplink radio resourceallocation method for allocating, at a radio base station, an uplinkradio resource used for uplink user data transmission to a mobilestation, comprising: a first target value assignation section configuredto assign a first target value as a target value for total receivedpower in a particular cell of the radio base station, the first targetvalue used when the radio base station allocates the uplink radioresource.